Alectinib is an anaplastic lymphoma kinase (ALK) inhibitor which standard initial treatment for patients with advanced ALK rearranged non-small-cell lung cancer (NSCLC). The current study was planned by the incidental observation of non-immun hemolysis signs in several alectinib-treated patients, and its aim was to comprehensively characterize eritrocyte changes under this drug.

We analyzed retrospectively 13 patients treated with alectinib for ALK+ NSCLC at the Bakirkoy Sadi Konuk and Kartal Dr Lutfi Kırdar Hospital Medical Onkology Depertment.Almost all patients were consulted with the hematology clinic because of anemia and elevated lactate dehydrogenase during alectinib.Laboratory tests requested for characterization of anemia included reticulocyte count, indirect bilirubin,haptoglobin, direct antiglobulin test, and LDH.All patients were examined by peripheral smear

The analyzed patients, hematological tests results are showed that: Anemia was present in approximately all of patients and was mostly mild, (lowest hgb 8.5gr/dl).Reticulocytes were increased and the direct antiglobulin (Coombs) test was negative in all patients. Peripheral blood smears showed signs of eryptosis, abnormal red blood cell morphology in all patients, with anisocytosis, a predominance of acanthocytes, as well as occasional echinocytes, spherocytes, dacrocytes and rare fragmentocytes

We have reported 13 cases of significant alterations in erythrocyte morphology secondary to alectinib. Patients predominantly showed mild anemia, but one patient developed significant Coombs-negative hemolysis. In this case, hemolytic markers improved after alectinib was discontinued. This study highlights the need for both clinicians and haematologists to be observant for unrecognised off-target effects of novel agents.